Segmented Fuse Element for High Voltage Capacitor Banks
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Solution Overview
Problem
High voltage power capacitor banks face failures due to intense arcs when individual capacitor sub-units fail, leading to complete bank failure and high power losses, with existing fuse solutions being costly and prone to manufacturing errors and heat issues.
Innovation Solution
A fuse element design featuring multiple parallel metal sub-strips with serial isolating gaps, integrated into a composite material with a polymer base layer, allowing for shorter fuse lengths, reduced power losses, and improved reliability, while being easier to manufacture and handle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single wire fuse elements are used to protect capacitor sub-units, then the capacitor bank safety is improved, but the fuse length must be very long (100 mm or more) which increases power losses and the manufacturing complexity increases
Solution Approach 1:
The fuse element is segmented into multiple parallel metal strips (at least two, preferably three or four) instead of using a single wire. Each strip acts as an independent current path, allowing the fuse to achieve the required current carrying capacity and response characteristics without excessive length. The strips are arranged parallel to each other and connected at their ends, creating a compact structure that reduces both length and manufacturing complexity while maintaining safety functionality.
Solution Approach 2:
The invention transitions from a single-dimensional wire fuse to a multi-dimensional parallel strip structure. By arranging multiple strips in parallel and connecting them at their ends, the fuse achieves equivalent electrical performance in a more compact spatial configuration. This dimensional transformation allows the fuse to meet safety requirements with reduced length and simplified manufacturing compared to traditional single wire designs.
2Device complexity
If single wire fuse elements are used, then the structure is simple, but the power losses are high due to the long fuse length required for high voltage applications
Solution Approach 1:
The fuse element is divided into multiple parallel metal strips that share the current load. This segmentation reduces the current density in each individual strip, allowing for shorter strip lengths while maintaining the same total current carrying capacity. The parallel arrangement provides multiple current paths, reducing overall resistance and power losses compared to a single long wire design.
Solution Approach 2:
Multiple parallel metal strips are combined and connected at their ends to form a unified fuse element. This merging of multiple conductive paths creates a parallel electrical circuit within the fuse, effectively reducing the total resistance and power losses. The combined structure maintains electrical equivalence to a shorter single conductor while providing the safety function.
3Loss of energy
If two wires are used in parallel to reduce fuse resistance, then the heat losses are reduced and sensitivity to wire diameter deviations is reduced, but the manufacturing becomes more complex with more soldered connections required
Solution Approach 1:
The fuse is segmented into multiple parallel metal strips with simple end connections. This segmentation achieves the benefit of reduced heat losses through parallel current paths while minimizing manufacturing complexity by using straightforward end-to-end connections rather than multiple soldered joints. The parallel strip structure naturally provides current sharing and reduced sensitivity to individual strip variations.
Solution Approach 2:
The invention applies local quality by concentrating the electrical connections at the ends of the parallel strips rather than along their lengths. This localized connection approach simplifies manufacturing by reducing the number of connection points required, while the parallel strip configuration throughout the body of the fuse maintains the benefits of reduced resistance and heat losses.
4Reliability
If longer fuse elements are used to provide sufficient isolating length, then the voltage hold-off capability is improved, but the fuse resistance increases leading to higher power losses
Solution Approach 1:
The fuse element is segmented into multiple parallel strips that provide both current carrying capability and isolating function. The parallel arrangement allows the fuse to achieve adequate voltage hold-off capability through the combined effect of multiple strips while maintaining shorter individual strip lengths. This segmentation enables the fuse to provide sufficient electrical isolation without the excessive resistance that would result from using a single long element.
Solution Approach 2:
The invention uses a multi-dimensional parallel strip configuration to simultaneously achieve voltage hold-off capability and low resistance. By arranging strips in parallel and connecting them at their ends, the fuse creates multiple current paths that reduce resistance while the overall structure maintains the necessary isolating length for high voltage applications. This dimensional approach resolves the trade-off between isolating length and resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces power losses by up to 25%, decreases manufacturing and labor costs by 50%, and enhances reliability with faster current limitation and reduced energy discharge, minimizing damage and noise.
Implementation Method 1
The fuse element comprises an active response part formed by at least four strips of metal with at least respectively two metal sub-strips being parallel
Implementation Method 2
The fuse element comprises an active response part formed by at least four strips of metal with at least respectively two metal sub-strips being parallel on a base layer of polymer material
Data Source
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Figure 7~9
AI summary
A fuse element (10) and a method for manufacturing the same, are provided whereby the fuse element (10) consists of an active response part which is advantageously formed by at least four metal sub-strips (9) of an elongated fuse metal foil with at least respectively two metal sub-strips being parallel being provided by at least two elongated recess within one or two self-supporting elongated fuse metal strips, with the at least two recesses being provides in serial alignment along the respective fuse metal strip, including leading and trailing parts for electrical connection of each fuse element (10), the elongated fuse metal foil can be reinforced by an elongated dielectric base layer made of polymer material. Accordingly, performance of such a fuse element (10) can be increased and manufacturing costs can be decreased. The invention especially can be applied to a plurality of capacitor sub-units being integrated in housings and submerged in a cooling and insulating liquid within the housing.